Masonry products have been widely used in the construction industry and include building materials such as cementious materials, concrete, brick, tile, stone, grout, and like substances. Driveways, garage flooring, concrete block, brick fronts, fireplaces, fireplace hearths, as well as tiled floor, wall and counter top surfaces are exemplary applications. Masonry surfaces are porous and if left unprotected can deteriorate from exposure to water and they can become discolored. For example, water penetration can cause spalling or lead to discoloration via microbial growth. Tiles and grouts employed in homes come in contact with various foods and liquids, e.g., fruit juice, coffee, oil(s), ketchup, mustard, and the like that can cause discoloration. Motor oils, brake-oils, and transmission fluids can cause discoloration of garage floors. Therefore, it has been common practice to coat masonry surfaces with materials capable of rendering them resistant to water, oils, and other contaminants.
Coatings for masonry have been generally of two types, one type being a waterproof coating and another type being a water repellant coating. A coating of the waterproof type renders the surface completely impervious to both liquid water, water vapor, and other contaminants. On the other hand a coating of the water repellent type renders the surface impervious to water in the liquid phase but permeable to water in the gas phase.
Exemplary of materials for the waterproofing of masonry surfaces are water proof membranes such polyvinyl chloride, polyethylene, butyl rubber, and sealants such as tar, asphalt, paints, polyurethane, epoxy or mastics. While these waterproofing agents can offer excellent resistance to water penetration and other contaminants, they can alter the appearance of the masonry surface, e.g., they may change the color of the surface or leave it with a shine. Waterproofing treatments can also trap moisture within the masonry surface and promote spalling.
Exemplary of water-repellent treatments for masonry surfaces include metal stearates, oils, waxes, acrylates (both polymers and monomers), silicones (solvent-based and emulsion), siliconates, silanes and, fluorochemicals. In contrast, to water proofing coatings, water repellent coatings, because they are permeable to water vapor, do not trap moisture and, therefore they can reduce spalling. In addition most water repellent coatings do not alter the appearance of a porous masonry.
The following references are illustrative of compositions and processes for the treatment of masonry surfaces to provide water repellency and other properties thereto:
U.S. Pat. No. 2,412,470 discloses a process for treating a solid body to render it water repellent which comprises contacting said body with a composition containing, as the active ingredient thereof, a mixture consisting essentially of from about 2.8 to 99.2 weight percent trimethyl silicon chloride and from about 97.2 to 0.8 weight percent silicon tetrachloride.
U.S. Pat. No. 2,574,168 discloses a process for rendering porous masonry structures water repellent by applying a dilute liquid comprising an organic solvent solution of a silicone resin in its B-staged partially condensed form to the surface.
U.S. Pat. No. 3,772,065 discloses the use of alcoholic solutions of alkyltrialkoxysilanes to impart water repellency to masonry surfaces.
U.S. Pat. No. 4,360,994 discloses the use of latex compositions comprised of an acrylonitrile/butadiene copolymer for providing water repellency to masonry surfaces.
U.S. Pat. No. 4,648,904 discloses the use of an aqueous emulsion of a hydrolyzable silane in treating masonry surfaces in providing water repellency thereto.
U.S. Pat. Nos. 4,717,599 and 4,753,977 disclose methods for rendering masonry water repellent which comprises (a) contacting the masonry with a solution comprising an organopolysiloxane resin selected from the group consisting of resins containing R3SiO0.5 units and SiO2 units, resins containing R3SiO0.5 units, and resins containing R2SiO2 units and SiO2 units, and (b) evaporating the solvent.
U.S. Pat. No. 5,919,527 and U.S. Pat. No. 6,120,892 disclose the use of waterborne fluoropolymer solutions for treating hard surfaces, such as masonry, to impart water, oil, and stain repellency.
U.S. Pat. No. 5,424,474 disclose the use of fluorine-containing phosphate esters on hard surfaces, such as, ceramics, stone, masonry, wood, and plastics to repel water, grease, oil, and dirt.
JP2002138241 (abstract) discloses a water repellant coating containing organic solvents, alkoxysilanes, and ethylene polymers for use in architectural concrete. It was reported that a paving concrete board was coated with a solution containing ethylene-vinyl acetate polymer 5, decyltrimethoxysilane 10, and Solvesso 100 (aromatic hydrocarbon) 85 parts, dried, coated with Mowinyl 700 (methyl methacrylate-butyl acrylate copolymer emulsion) and dried, resulting in good appearance after spraying with water.
JP10287482 (abstract) discloses surface finishing agents for forming coatings on porous concrete. The agents are synthetic resin liquid emulsions showing high water resistance and gas permeability. The resins may mainly contain ethylene-vinyl acetate (EVA) polymers or acrylic ester-styrene copolymers.
CS252126 (abstract) discloses poly(vinyl acetate)-containing coating with resistance to water. The coating is reported to be useful on brick, concrete, and other surfaces for preventing staining and is prepared from an aqueous composition containing poly(vinyl acetate) 10-15, white pigment 8-15, CaCO3 8-15, preservative based on mineral oil 6-12, alkaline C10-18-alkyl sulfates 0.05-0.1, water-soluble dye 0.1-2, and disinfectant 0.1-2%.